Sewing-machine shuttle bobbin



Dec. 34), 1930. H. G. JOHNSON SEWING MACHINE SHUTTLE BOBBIN Filed Dec. 4, 1928 .ZWW/

A7 M% W- 3% /1 Patented Dec. 30, 1930 UNITED STATES PATENT OFFICE HENRY G. JOHNSON, OF EAST HAMPTON, CONNECTICUT, ASSIGNOR 'IO SUMMIT THREAD COMPANY, OF EAST HAMPTON, CONNECTICUT, A CORPORATION OF MAINE SEWING-MACHINE SHUTTLE BOBBIN Application filed December 4, 1928. Serial No. 828,757.

portions of the tube ends..

The shuttle is usually provided with a spring or brake exerting sufiicient frictional pressure on the bobbin to produce a suitable tension on the thread and prevent the bobbin.

from spinning or overrunning in the shuttle, .as shown, for example, by the patent to Bates, No. 569,316, October 13, 1896.

The brake bears on one of the bobbin heads, and not only regulates the rotation of the bobbin, but also has a tendency to force the head sidewise toward the opposite head. The margins of the head orifices should be so firmly engaged with the periphery ofiithe tube as to prevent sidewise movement of either head by pressure of the brake thereon. Heretofore the head orifices have been circular, and have not been adapted to grip the tube with sufiicient force to prevent independent rotation of the tube in the heads, and inward sidewise movement of the head with which the spring or brake contacts so that when thread is being drawn from the bobbin, the thread mass and tube are liable to be rotated independently of the brake-pressed head, the rotation of which is opposed by the brake. The independent rotation of the thread mass and tube causes the margin of the orifice in the brake-pressed head to wear the tube, so that the pressure of the brake on said head forces it toward the opposite head, and so increases the pressure of the brake-pressed head on the thread mass as to objectionably increase the tension of the thread being withdrawn, and cause breakage thereof.

The object of my invention is to obviate this objection.

Of the accompanying drawings forming a part of this specification,-

Fi re 1 is an end view of a bobbin to whic my invention relates.

Figure 2 is a side view of the same.

Figure 3 is an enlarged view of one of the heads of the bobbin.

Figure 4 is a section on line 4-4 of Figv Figure 5 is an enlarged section on line 5a5 of Figure 1.

I Fi ure 6 is an enlarged end view of the bobbin, a portion being shown in section on the plane indicated byline 6-6 of Figure 5.

Figure 7 is an enlargement of a portion of Fi re 3.

igure 8 is an enlargement of a portion of Figure 6.

The same reference characters indicate the same parts in all of the figures.

The bobbin is composed of a cylindrical cop tube 12, an annular thread mass 13, universally wound thereon, and discoidal heads 14 of sheet material, preferably paper, each having a central orifice 15, the orifices of the heads receiving the ends of the tube 12. The heads are confined on the annular ends of the thread mass 13, in accordance with the usual practice, by upset portions of the tube ends as shown by Figure 5.

Heretofore the margins of the head orifices 15 have been circular and concentric with the peripheries of the heads, the tube ends closely fitting the margins of the head orifices, and bearing with a uniform pressure on all portions of said margins, so that the hereinafter described locking of the heads to the tube ends, to prevent independent rotation of the tube in the heads, is not effected.

In carrying out my invention I impart to the margin of each head orifice 15 a non-cin cular form, which is such that the margin includes a plurality of tube-grip ing portions which are nearer the centers 0 the heads than other portions alternating with the gripping portions, the relative proportions of the tube and the head orifices being such that said gripping portions exert a suflicient ipping pressure on portions of the perip cry of the tube, to lock the heads to the tube and prevent independent rotation of the tube in 1 the heads.

The non-circular form is preferably rovided by imparting the octagonal fgrm shown by Figures 3 and 7 to the margin of the orifice, so that said margin includes a plurality of strai ht-edged gripping portions 16, and a plura ity or reentrant portions 17, alternating with the gripping ortions.

A line 18 (Figure 7) exten ing between two diametrically opposite reentrant portions 17, is longer than a line 19 extending between two diametrically opposite gripping portions 16. The length of the line 18 is substantially equal to the diameter of the tube 12. It will be seen, therefore, that when the heads are forced on to the ends of the tube, the gripping portions 16 are compressed and caused to exert a greater gripping force on .the tube than the reentrant portions 17, the ,margin of the head orifice being caused to conform to the eriphery of the tube, as in dicated by the ull line circle 20 in Figures 6 and 8.

I have found that when the head orifices are formed as shown, and the relative diameters of the tube and the orifices are as above described, the gripping pressure of the margins of the head orifices on the periphcry of the tube is sufficient to prevent independent rotation of the tube 1n the heads, and obviate the objection heretofore stated.

I do not limit myself to the octagonal fiorm of the margins of the head orifices, it being obvious that said margins may have other non-circular forms capable of accomplish-' ing the described result.

I claim:

A shuttle bobbin composed of a cylindrical cop tube, an annular thread mass wound on said tube, and discoidal heads of sheet material having central orifices receiving the ends of the tube, the heads being held against the annular ends of the thread mass by upset portions of the tube ends, and the margins of said head orifices each includin a plurality of tube-gripping portions which exert greater pressure on the tube than other portions alternating with said gripping portions, the diametrical distance between the latter corresponding to the exterior diameter of the tube, whereby said gripping portions will exert a suflicient gripping pressure on portions of the periphery of the tube to prevent rotation of the tube and thread mass relative to the heads.

In testimony whereof I have affixed my signature.

HENRY G. JOHNSON. 

